Steam-generator.



W. MITCHELL.

STEAM GENERATOR.

APPLICATION FILED SEPT-29,1913.

1 139 4300 Patented May 11, 1915.

3 SHEETS-SHEET I.

- a 24 26 7 53 40 1: 1:: amen Wot 56 $0 2 WW 9 36' W251) M THE NORRIS PETERS 60., FHOTO-LITHO.. WASHINGTON D r W. MIICHELL.

STEAM GENERATOR.

APPLICATION FILED SEPT.29, 1913.

Patented May 11, 1915.

3 SHEETS-SHEET 2- THE NORRIS PETERSICOH PHOTO-LITHQ, WASHINGTON. D. C.

3 SHEETS Patented May 11, 1915.

W. MITCHELL.

STEAM GENERATOR.

APPLICATION FILED SEPT.29.1913.

wi/bvmooeo THE NORRIS PETERS co. PHOTC-LITHQ, WASHINGTON. u. r

IINITE TATE FATE @FIIQE.

WILLIS MITCHELL, OF MALDEN, IVIASSACHUSETTS, ASSIGNOR TO "WILLIS MITCHELL COMPANY, INC., OF NEW YORK, N. '21., A CORPORATION OF NEW/V YORK.

STEAM-GENERATOR.

Application filed September 29, 1913.

T aZZ whom it may concern;

Be it known that I, VVILLIs MITCHELL, a citizen of the United States, residing at Malden, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Steam- Generators, of which the following is a specification.

The object of this invention is the generating of steam by the more complete and effectual utilization of vibration, adapting and applying the positive and negative action produced by heat and cold, in the construction of a steam-generator, non-explosive, constant in reference to power, and capable of providing an excess of dry, anhydrous, or superheated, steam, by one single operation, and without the use or need of any super-heater or steam dome for additional treatment, in quantity beyond what the engine can consume, and supplying the same in gaseous form and an auxiliary airtank, utilizing the same by its expansive power therein to force water to the generator. The steam thus generated is higher in degree and more powerful than that recognized under the commonly accepted term, superheated; it is steam more aeriform, more refined, than that which has been known as superheated. Its vibrating rate or degree is such that a match presentcd to it, after it has passed through the engine, is instantly ignited by the friction and vibratory disturbance of the escaping jet, a manifestation not possible with the steam generated, however superheated, in any boiler or generator produced prior to my invention.

My generator includes a tube wound in a series of double helices arranged around the burner, and combines therewith air-pressure tanks arranged to receive the vibratory action from the heliceswhich vibratory action is transmitted and continued through the water-pressure tank, and arranged to break up the water in the water-pressure tank into its gaseous elements, thus adding more pressure in this tank, and this supply taking the place of the water being forced into the helices, and also arranged to utilize the expansive power of the air compressed in the pressure-tanks, the same continuing to'force the water to the generator, thus maintaining a continuation and regularity Specification of Letters Patent.

Patented May II, I915.

Serial No. 792,297.

of power for as long a time as there is any water in the pressure-tank.

Suitable means, hereinafter described, are provided for preventing any excess of pressure, for re-supplying water to the pressuretank, and also for the absolute prevention of any danger of explosion.

The constituents of the steam thus resolved are left in such condition that they can be readily condensed into water again and returned as a new supply to the helices for regeneration into steam.

This generator and its appurtenances, in combination with the water-feed tank, the gas-burner and the fuel gas-generator and carbureter-injector supplying the same, together constitute my new system of steam generation, using the gas from oil as fuel. The gas-generator and burner employed herein constitute the subject matter of separate applications for patents wherein their novel features are claimed. The dry and rarefied steam produced thereby is, nevertheless, easily liquefied by condensation, owing apparently to separation of constituent elements effected by the vibration aforesaid, which, nevertheless, leaves them with strong tendency to reunite in liquid form, becoming water again, if desired, on being directed against a condensing plate as they leave the Water-tubes of the generator.

After coming to the conclusion that water is evaporated and steam is produced by vibration, brought about by positive and negative energies through or by contact with heat and cold, I searched for the fundamental nrinciple and proof of the same and spent twelve years in study and experiment at heavy outlay.

My most interesting demonstration of the principle involved is illustrated in Figure 10 of the accompanying drawings, as showing the breaking up of the molecules of cold water by vibration, the water remaining cold and being converted into gaseous elements. Ihis apparatus and its operation are described here as preliminary in their nature and not forming part of the steam-generator which is the subject of this specification, but preparing the way for adequate comprehension of the novel method of the said ge erator.

I employed, as shown in said Fig. 10, a glass U- shaped receptacle B, having metal tached thereto for pumping air into the said receptacle, a valve A preventing it from escaping. I removed said plug and filled said receptacle B two-thirds full of water, then replaced it, and attached the pump at E, pumping in air until the water was forced up the column on the opposite side, up toward the right hand cap D above the level of the connection at F, between the right limb of this receptacle and the generator coil F brazed to a copper disk C. As the air above the water in this limb cannot escape in such conditions, it makes an airchamber or cushion and receives the same pressure as at the other limb of the receptacle and over the other column of water. The air was arranged thus to demonstrate that the'pressure was not maintained by steam going back into my pressure-tanks, but by the force of vibration, which was breaking up the molecules of water into gaseous form. I then poured some alcohol into a receptacle M and ignited it, thereby heating the said disk and coil very quickly. I then opened the valve H of said coil and let out the contained air, which was followed by water, the latter being converted into superheated steam. At the opening of said valve the water began to boil at the surface at L in left limb of the receptacle under cap C, as indicated by the arrows, being broken up at this point into gaseous elements which took the place of the water that was being converted into steam. This boiling cannot be due to steam or gas passing back through the U-shaped receptacle, for it would naturally take the path of less resistance through coiled tube F, escaping into the chamber at its opening J. But vibratory energy passing through the water in this manner would produce this ebullition and reduction to aeriform fluid; and such vibration is the eflicient agent in the case. I have caused this vibration to pass through a resistance coil, using up the energy just as if electric energy was thus passing.

Besides the broad features of my inven tion, it includes a number of special constructions and combinations of the various parts of the'generator. Thus the watertube is wound in a series of double helices arranged around the burner and wound so as to change the direction of current in each helix, and preferably to reverse the order of said changes once in the series. I also employ a double-walled generator-casing,

the inner shell of which has many small holes, causing the general distributlon of the heated products among all parts of the helices, and combine therewith novel means for spacing the casing-shells apart and hold ing the helices in place; I also provlde a The present application does not claim the especial construction of the helices de-.

scribed nor the other details of'the generator proper, these features being reserved for .a new divisional application.

In the accompanying drawings? Fig. 1 represents a perspective view of my steamgenerator, the outer shell being partly broken away; Fig. 2 represents on a larger scale a front elevation of the same, the front wall being removed to exhibit the series of double helices in position; Fig. 3 represents on a still larger scale a detail perspective View of one of the double helices; Fig. 4 represents the two helices composing it, separated and set side by side; Fig. 5 represents a detail view, in elevation, of the pressure-tanks and their tubular connections; Fig. 6 represents a detail view in vertical section of the air supply pipes and the concentric Water connections; Fig. 7 represents a detail view of a by-pass valve; F ig. 8 a detail. view of a check valve; Fig. 9 a-detail View of one of the bolts; Fig. 10 a diagram of certain experimental apparatus; and Fig. 11 is a detail view of the shield-form valve proper of the relief or by-pass valves and its perforated disk.

The continuous water and steam pipe of my generator enters through the exterior casing thereof at a, preferably in the bottom, and leaves it at 6, preferably in the top, being wound between these points into a nearlycircular series of double helices,each of which consists of an outer helix 1 and an inner helix 2, this series being arranged against the circular wall of the generator and around its horizontal burner 3, leaving a space 4; (Fig. 2) at the bottom, below said burner, for the generator and its pilot preheating devices. The forward parts of these extend through the front wall of the outer casing at 5 and 6, as shown in Fig. 1, said generator and appurtenances being omitted from Fig. 2 for greater clearness and because they are not a part of this invention, their position being suiliciently indicated by Fig. 1, to aid in explaining the action of'the relevant elements. The cylindrical body of the generator casing is formed of two concentric cylindrical shells 7 and 8, which are spaced apart by nuts 9 on bolts 10, the shanks of which pass between the proximate helices and are provided with broad wedge-form heads 11 for holding them in place. At the ends of the series screw-tapped nuts 12, similar in form to said heads 11, are engaged by short screws 13, the heads of which have the form and function of said nuts 9, and drawn into the angles between the terminal helices of the series and the inner casing shell 7. By these devices 9, 10, 11, 12, and 13, all the helices are securely clamped in position and a draft space 1 1 is provided also by them between the two shells of the casing.

As the products of combustion are inoffensive, and not great in volume, no smokeflue or funnel is needed, but the inner shell is provided at numerous points with small outlet holes 15, compelling a general distribution of the said products of combustion and heat among all the coils of the helices before making their escape into space 14. The outlet shell 8 has only a single outlet 16, which is in its bottom, compelling the small streams of such heated gaseous matter, after they issue through the holes 15, to pass along or around the inner shell 7 through space 14, converging at this final bottom outlet. They are hardly perceptible to one standing near, as there is no smoke or steam and the combustion is nearly perfect, mainly by reason of improvements in the generator and burner which form no part of the subject matter of this applica tion; but also to some extent because of the tortuous path which they are compelled to follow after leaving the burner, during the earlier part of which they are in or very near the flames and afterward in close contact with the heated inner shell 7 Preferably the first winding of the watertube is in the form of the outer cylindrical helix 1 of the first double helix, reversing at the rear end thereof to wind the inner helix 2 of the same concentrically within it; then it passes to the outer helix 1 of the next double helix, beginning again at the forward end thereof and so continuing until half of the series is wound, then passing in a long curve 19 outside of the position of the remainder of the series and beginning at the front end of the inner helix 2 of the last double helix, reversing at the rear of this to wind the outer helix 11 of said double helix, then winding the inner helix of the next double helix, and so backward to the middle of the top of the series where it ends at 6. Thus the water as it turns to steam and then to permanent rarefied gaseous product, flows around the burner subject to its heat in a very devious current which is suddenly reversed at the end of the first helix of each double helix, the direction from left to right being changed to that from right to left for example in each double helix of the first half of the series,

and the direction from right to left being similarly changed to that from left to right in each double helix in the second half of the series, also the general course being toward the top of the series in both halves thereof. Furthermore, the winding in reversed series makes the two helices in each double helix cross each other and intercept more perfectly the radiant heat and hot gaseous matter flowing from the burner into and through said helices, in order that it may be applied to the best effect. This is aided by the provision for escape in minute quantities through small outlet holes at many points, as above stated. With such a construction of the shell and helices very little of the heat can fail of doing its full service. But in addition, the frequent interruptions and reversals of the water and steam current will tend to break up the particles thereof, to lessen cohesion and bring it more nearly to a finely gaseous state, as is obvious when streams visibly dash together, producing spray and mist, or are torn into vapor by contact with obstacles or by friction along their beds. This enables the heat to act with greater eflicacy, a part of its work being done for it by more strain, jar and attrition. Also, there must be a generation of electricity and, perhaps, other subtle vibratory action, contributing to the comminuting and gasifying action. The influx of water at the bottom of the generator has been found more efficient and satisfactory than if it were at the top, inasmuch as the heat derived from the burner and circulating currents of hot gases is permitted to exert its greatest effect just before the steam leaves the generator. This is due to the fact that the gases circulate quite to the top of the generator casing and that their lighter elements necessarily tend up to that so that the temperature is necessarily at its highest in the neighborhood of the outlet helix and the pipe running therefrom.

A main pressure tank 20 and auxiliary pressure-tank 21, connected together by an air pipe 22, governed by a hand-operated valve 23, are attached to the rear end of the main generator casing and have the function of preventing explosion and insuring regularity of steam generation in the helices, being aided therein by a system of tubes and valves, as hereinafter set forth. Auxiliary tank or reservoir 21 always contains air, normally under pressure, and never contains anything else. The main pressure tank or reservoir 20 normally contains both water and air, the latter under pressure and acting as an air-spring on the water which enters the lower part of said tank.

From the bottom of tank 20 a short waterpipe 2 1 extends downward, having at its lower end a coupling 25. An upright inner provided with an air inlet valve 35.

water pipe 24, of course, has no connection with the interior of any of these pipes, but receives in its side a water pipe 28 connected with a water-supply pipe 29, which extends to the main reservoir by way of the pump driven by the engine. A check-valve 30 in said water-supply pipe 29 acts to prevent the water from being forced back to the pump by the tank pressure. The water passes from tank 20 through a generator supply pipe 31, governed by a hand-operated valve 32, to the generator, said pipe 31 entering through the front thereof and j oining the first double helix at a. as stated. This generator-supply tube 31 is provided with a by-pass branch tube 33, joining it both before and behind said valve 32, so as to provide a possible passage when this valve is closed, said by-pass being provided with an outwardly opening relief or bypass valve 34, which will open under excessive pressure to permit a back flow of water from the generator to the tank, its function being that of a safety valve arranged to cause the cutting off of the steam supply. In like manner the water-supply pipe29 is provided with a by-pass branch tube 36, running from a point of said pipe between its check valve and the pressure tank to a point of said pipe on the other side of said check valve, or directly to the .main reservoir. This by-pass 36 is provided with a relief valve 37, opening in case of need toward the source of water supply. A drain pipe 39, having a hand-operated valve 40, connected with pipe 31, affords a convenient means of draining the water from tank 20 at will.

In operation I admit air to the tanks 20' and 21 through air-inlet valve 35 until the pressure reaches one hundred pounds in the two tanks, the connection between them being open. I then pump water into the tank 20 until it compresses the air to a pressure of two hundred pounds, which point is reached before the water is at thelevel of the vertical air pipe 26. I then cut off tank 21 from tank 20 to close their connection, thus bottling up that amount of pressure in said auxiliaryv tank 21. I then draw out the water from the tank 20 by suitably turning valve 40 and force in air simultaneously till I have a hundred pounds of pressure, and pump in water as before till I have three hundred pounds of pressure. Then I, 0

the pressurefor example, four hundred r pounds, at or a little beyond which the en gine is set to run. The by-pass valves are adjusted to yield at the same pressure. The

burner is then supplied and lighted and the operation of generating steam begins.

If no water be supplied to the generator until its helix coils are heated exceedingly, and the water be then let in under pressure, no harm will follow. Of course, insuch conditions there will be a sudden generation of steam in the hot coils, but as soon as there is a pound more pressure in the helices than in the pressure-tank 20, this excess of pressure will prevent water from'entering the coils and thus stop the fiowto the generator, thus ending the generation of steam, for the generator makes steam'only while supplied withwater. Should the throttle be open, it will work just the same, for "there would'not be any more pressure in the generator than in the pressure tank. Again, if the generator be supplied with water, the fire hot and the throttle and valve 32 closed, of course steam will be generated, but without danger, for the bypass 33 around said valve 32 affords an outlet to the pressuretank 20, its relief valve 34 yielding toward the latter. If steam be thus driven out, it will be condensed into water on the way to the pressure tank 20. If it should cause undue pressure in said tank, the water would be forced out of the latter to the main reservoir or other source of water supply through v the other by-pass 36 and its relief valve 37..

from a water reservoirby means of a pump I operated by an engine supplied with steam by saidv generator, the generator discharge at b will be directed suitably, in part at least, to said engine, the speed being gov erned by the throttle in the ordinary way.

Such combinations of cooperating mechanisms may safely be left untended for a time. If just starting up, the, infiowing water will drive the air out of the helices and be converted into steam before it passes through the coils, thepump supplying the pressure-tank, the pressure-tank supply ng the generator, the generator supplying the engine, and the engine driving the pump in a continuous circuit of actlon, automat cally operated and automaticallyregulated. Thethrottleand valve'32 should be 7 open also, and the valve governing the air connection between pressure-tanks 20 and 21, that the full requisite air-pressure may be available.

The pressure-tank 20, as the parts are con structed, arranged and combined by me, will be about two-thirds full of water before the relief valve 37 will open and let the water from said tank back through the bypass 36 to the main source of supply, notwithstanding the pressure is being maintained; for the entering water is very light and foamy, being aerated by vibration, so that its condition is neither liquid nor gaseous, but intermediate and less adapted to transmit vibrations than either. If it were water in a pure state, or pure steam, a less volume would be supplied before the expansive power of the air compressed by it, reinforced by the inflow of such water would operate to force the water from the tank through said by-pass 36 and relief valve 37. The relief valves, of course, are adjustable to any pressure required or which may suit the engine in use, but, as before stated, a working pressure limit of four hundred pounds is found convenient. It will be observed that I use air-pressure, partly produced by inlet water pressure, to balance and regulate steam pressure, by letting out excessive steam or water acted on thereby and by stopping the water supply whenever the pressure exceeds the predetermined amount.

In the older kind of boilers it is necessary to rely on the pumps to maintain an ample supply, and, if this runs low, danger and injury will follow, but in my generator, as stated, the running low of the water can do no harm.

In the changes of movement between pumping water into the pressure-tank and back and forth from the reservoir there are intervals of inaction for the valve 37, which is kept open while the water goes back into the main reservoir and kept closed while the pump is forcing water into the pressuretank, relieving both the said valve and in less degree its by-pass valve 36 from strain and wear, which would be considerable if said valve were continually moving and if there never were a cessation of flow through said by-pass.

The adjustment of the relief valves 34 and 37 before referred to is preferably by means of a nut 40 and a screw-post 41, said nut being in contact with a helical spring 42, increasing or decreasing the tension and resisting power of said spring. By screwing very tightly down the nut 40 of relief valve 37, the latter may be made practically a fixture for special occasions, as when the generator is used on a motor truck climbing a steep-hill andneeding'a'bundant water. The pumps will then at once supply more water, making more steam; the extra heat required is provided by supplying extra fuel gas to the burner, using means not shown, for they do not form part of this invention, the throttle being opened correspondingly wider at the same time.

I do not have to wait for steam pressure in starting, for I do not rely on the steam pressure for this, but on air and water pressure and the vibratory action, tending to transform the water into gaseous condition irrespective of heat. I find that practically much less water is required for this generator than in tubular boilers commonly in use. The effervescent commotion of the water due to forcing it against compressed air in pressure-tank 2O prepares it in advance, so that it is brought to a gaseous state by the use of less heat than in the ordinary generation of steam.

In using this generator on a motor car run by an inexperienced operator the relief valve on the by-pass of the water inlet pipe can be set to provide for a speed of nine or ten miles an hour, and the vehicle will not exceed that limit, even if the throttle is wide open, unless in coasting, and the movements may be operated to retard motion even then.

By this generator T can furnish thirtyhorse power for ten cents an hour where it now costs sixty cents an hour with a gasolene engine of the same power.

Such a generator may of course be used to supply the pipes of a steam-heating system for house or car, and the outflowing steam directed from it upon the snow, or operating to heat snow scooped up, for supplying water is exceedingly efficient. It may also be used as a fire-extinguisher by conducting a hose from the pressure-tank direct to the fire.

I do not confine myself to the special form of relief or by-pass valve shown, but

it will often be convenient to use for valves 34 and 37 a semi-cylindrical depending shield or slide valve 54 adapted to cut off the back flow and carried by a piston 43, which is lifted by such flow against the resistance of a spring .42 surrounding a stem 46 and governed by a screw-plug 47 in the valve casing 41. This piston may have a flexible packing 50 clamped to it by a disk 51, below which is a perforated disk 45,

having the slide valve or cut-ofi' valve 54- properly attached to it, these parts being held together and in place by a screw 58. Their construction and combination form no part of the present invention and are illustrated merely to make the operation clear.

The check valve hereinbefore described mayconsist of a ball valve in a casing havchanged by the substitution of any other well known form.

7 Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination with a series of watertube helices, means for heating the same and a generator casing surrounding them, a pressure-tank adaptedto contain air under pressure and tubularly connected to the inlet end of said series, and means for opening and closing such communication between them at will, but permitting back flow while it is thus closed when the back pressure from the helices exceeds a certain degree.

2. In combination with a series of watertube helices, means for heating the same. and a generator casing surrounding them, a pressure-tank adapted to contain air under pressure, a pipe connecting said pipe to the inlet end of said series, a hand-operated cut-off valve in said pipe, a by-pass branch around said valve and a relief valve in the latter to provide for return of fluid to the tank under pressure exceeding that of the latter.

3. In combination with a series of watertube helices, means for heating the same and a generator. casing surrounding them, a pressure-tank .tubularly connected to the inlet end of said series and adapted to receive and contain air under pressure, an auxiliary air pressure-tank, means of permitting the passage of air from the former tank to the latter, and the closing of such means of passage at will in order that air pressure may be accumulated in the auxiliary tank to aid the main pressure tank.

4c. In combination with a series of watertube helices, means for heating the same and a generator casing surrounding them, a pressure-tank, a water-tube connecting said tank to the inlet end of said series, an air supply pipeto said tank supplying air under pressure, an inner air pipe extending from sa1d air supply pipe up within said pressuretank to the upper part of the latter, an auxiliary air-tank, a branch air pipe connecting said inner air pipe to said auxiliary tank, valves controlling at will the latter air pipev and the main air supply pipe, and means for supplying water under pressure to the first pressure tank.

5. A pressure tank in combination with an inlet for air under pressure and means connected to said tank adapted at will to bottle the air under pressure and as needed to let of water supply and a by-pass and relief the yielding point of said valve may bevaried to suit the maximum pressure chosen.

7. A steam-generator in combination with a pressure-tank supplying water under pressure thereto, means for supplying air under pressure to said tank, a pipe conducting water under pressure to thelatter, a valve lief valve, permitting water under excess of pressure to flow back from said pressuretank to the main source of water supply and means for adjusting the yielding point of said relief valve.

8. A steam-generator in combination with a pressure-tank, means for supplying air under pressure thereto,means for supplying water under pressurev thereto provided with an adjustable relief valve for back flow under excess of tank pressure, a water pipe connecting said tank to said generator, a hand-operated valve for closing the same, and a by-pass and adjustable reliefvalve allowing return flow around this hand-operated valve under excess of generator pressure and means for accumulating pressure in said tank to the degree corresponding tothe adjustment of said valve.

9. In combination with a pressure-tank and means for accumulating air pressure therein to a predetermined degree, means for supplying water thereto provided with a relief valve adjustable to yield a pressure in excess of such degree and thus permitthe controlling the latter pipe, a by-pass and re- I return of the water, a steam generator and admitting air under pressure, means for ad-- mitting water under pressure, and means for drawing off the water at will, in combination.

with'an auxiliary tank protected against any inflow of water but tubularly connected at will with the air pressure in the main tank,

a steam-generator and a pipe connecting the latter to said main tank, the latter tube and the water supply tube being provided with relief valves and hand-operated cut-ofii' valves, or automatically operating checkvalves being provided where necessary to control the flow through any of the pipes.

11. The method of generating superheated name to this specification in the presence of steam directly from water, consisbtinglin crezfittwo subscribing witnesses. ing and applying vibration to rea up t e Water into gaseous form and permitting its WILLIS MITCHELL 5 escape rearward to an air chamber under Witnesses:

back pressure. JOHN T. WELOH,

In testimony whereof, I have signed my MADALINE B. CRAWFORD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

